Due to thermal mismatch, stresses develop in n-type diamond thin films when cooled down to room temperature from
deposition temperature. In this investigation, thermal stresses in diamond films deposited on silicon substrate are
calculated, the influence of temperature and film thickness on thermal stresses are also discussed. The results show that
thermal stresses are sensitive to deposition parameters, the thermal stresses increase with the increase of deposition
temperature, reach the maximum value of 0.724GPa at 1000k, and then begin to decrease. With the increase of diamond
thickness and substrate thickness, the thermal stresses decrease and increase respectively.
Monte Carlo simulations are adopted to study the space distribution of the particles in the mixture of CH4/H2/H2S/Ar considering the avalanche collision and dissociative ionization of electrons based on the theory of glow discharge in electron-assisted chemical vapor deposition (EACVD) system. The relationship between the space distribution and the recombination rate of H and CH3, CH3+ fragment particles is given. The dynamic process of the n-type doped diamond film is simulated under different gas pressure. The particle distributions of S, S+ and Ar+ are also obtained. The result is very important for investigation of n-type diamond film doping at low temperature.
High-quality Sulfur doped n-type diamond thin films have been successfully synthesized via glow plasma assisted hot filament chemical vapor deposition using gas mixtures of methane, hydrogen, Argon and hydrogen sulfide. Impacts of the volume ratio of hydrogen sulfide to methane RS/Con the structural and physical properties of the films have been systematic ally studied using various techniques such as Hall effect measurement, x-ray diffraction (XRD) and atom force microscope. We found that the carrier mobility is 474 cm2V-1S-1 and the electrical conductivity is 1.45Ω-1·cm-1at RS/C=6800ppm. The sheet resistivities of the films increase with increase of RS/C, reach the maximum at RS/C of 6200ppm, and then begin to decrease. Also, with increase of RS/C, a linear increase in the conductivities of the films is found, which is believed that higher RS/Cis favorable for the increase of electrical conductivity of sulfur doped diamond thin films.
In this paper, the experimental synthesis of diamond films and optical emission spectroscopy (OES) of the gaseous phase species are studied in the range of substrate temperature from Ts = 300°C to 850°C. The high quality sub-microcrystalline diamond films are successfully deposited at substrate temperature (330 ≈ 340)°C by adopting glow plasma assisted hot filament chemical vapor deposition (GPCVD). For the first time, in situ OES is applied to diagnose weak signal of GPCVD system when CH4 and H2 are used as the input gas, and the reactive species are identified in diamond growth processes. A primary model of diamond films growing at low temperature is presented by studying dynamic behavior for nonequilibrium plasma reactions.
Monte Carlo simulations are adopted to develop a numerical program to study the electron motion in the H2/CH4 gas mixture and the non-uniform electric field during diamond synthesis via Electric Assisted Chemical Vapor Deposition (EACVD) in order to understand this dynamical process. It is proved in this paper that there exists a reverse electric field near the substrate. With this reverse electric field, the effective radicals such as CH3+ and CH+ can be speeded up and impact on the substrate with a higher speed, thus increase the probability of bonding. At last the electron average energy distribution and the steady space distributions of the effective radicals such as CH3, CH3+, CH+ and H under this field distribution are given in this paper.
In this work, excimer laser (XeC1 308nm) is adopted to ablate the carbon target in order to deposit high quality nano-crystalline diamond films via electron assisted chemical vapor deposition (EACVD). In experiment, the temperature of substrate is about 300~450 degree Celsius, reacting gas is the mixture of methane and hydrogen in which volume ratio of methane to hydrogen is about 0.7 %, laser power density is 10-710b0 W/cm2. Experimental results show that the sharp peak in Raman spectra of sample films appears at 1332cm-1, which indicates crystalline diamond phase is formed in the samples. And the (lii) characteristic diffraction peak of diamond appears at 20=43.9° in X-ray diffraction spectra. Finally, the growth mechanism of diamond film at low temperature is discussed.
In this paper, diamond film is deposited at low substrate temperature by electron-assisted chemical vapor deposition (EACVD). The quality of diamond film is analyzed by the scanning electron microscope (SEM), Raman spectrum and x-ray diffraction (XRD). The results show that the high quality film of (111) orientation is deposited at low temperature of about 500 degree(s)C by the EACVD technique. Meanwhile, the mechanism of the deposition at low temperature is also discussed.